Steam-pressure gage



(No Model.)

M. McNEIL. STEAM PRESSURE GAGE.

No. 486,839. Patented Ndv. 22,1892.

qwmeooeo UNITED STATES PATENT OFFICE.

MURDOCK MCNEIL, OF BOSTON, MASSACHUSETTS.

STEAM-PRESSURE GAGE.

SPECIFICATION forming part of Letters Patent No. 486,839, dated November 22, 1892.

Application filed January 30, 1892. Serial No. 419,839. (No model.)

To all whom it may concern.-

Be it known that I, MURDOCK MONEIL, of Boston, in the county of Suffolk and State of Massachusetts, have invented certain new and useful Improvements in Steam-Pressure Gages, of which the following is a specification.

This invention has for its object to provide a simple, durable, and efficient means for operating the movable finger or pointer of a steam-pressure gage; and it consists in the improvements which I will now proceed to describe.

The accompanying drawing, forming a part of this specification, represents a front view of a steam-gage provided with my improvements, a portion of the dial and front of the casing being broken away and a part of the construction being shown in section.

In the drawing, a represents the casing of a steam-gage, and 1) represents the pointer, which is affixed to a central arbor c, to which motion is imparted through a pinion d, affixed to said arbor, a rack-segment e, meshing with said pinion and pivoted at f to a fixed support, an arm g, affixed to said rack-segment, a connecting-rod h, pivoted at one end to the arm g, and a flexible or elastic diaphragm t', which supports the opposite end of the connectingrod h and is arranged to receive pressure from water in the usual siphon-pipe j, connected with the casing a and with the source of steamsupply, said siphon-pipe always containing a quantity of Water, which is held by the steampressure against the diaphragm and prevents contact of the steam with the diaphragm.

The arrangement of the parts above described is such that pressure exerted in the direction indicated by the arrow :1; against the diaphragm i will move the rod h in the same direction, and thus, through the arm 9, racksegment (2, and pinion 01, will move the pointer 12 in the direction indicated by the arrow w, the pointer being thus caused to indicate an increase of pressure. When the pressure decreases, a spring is, affixed at one end to a cross-piece m, which is loosely mounted on the rod h, and at its other end to a cross piece m, which is engagedwith said rod by bearing upon a shoulder or collar h thereon, moves the rod in a direction opposite to that above described, and thus gives the pointer a backward movement over the dial.

The novel features of my invention are found in the diaphragm 2', rod h, spring in, and in the means hereinafter described for supporting said diaphragm, rod, and spring, said diaphragm, rod, and springbeing substituted for the usual Bourdon spring or tube.

The diaphragm 1) is composed of yielding rubber or other suitable elastic material and is fitted in a socket or holder j, which holder is of cylindrical form and is engaged with the casing to by means of a screw-thread formed on its periphery, engaging an internal thread in a recess or socket a, formed in said casing. The outer portion of the socketj' is reduced and connected by a coupling 0 or other suitable means with the siphon-pipe j. The diaphragm is formed to cover the passage extending through the reduced end of the holder j and is provided with a marginal flange 2', upon which bears a clamping or confining ring 10, said ring being externally threaded and engaged with an internal screw-thread formed in the holderj. The rod h is provided'with an enlarged head h, which bears upon one side of the diaphragm, said head being preferably concave, while the corresponding surface of the diaphragm on which it bears is preferably convex. This form is adopted to prevent the rod from slipping laterally in contact with the diaphragm and to retain the rod in a central position. diaphragm upwardly upon the head of the rod, as shown, the diaphragm being virtually a rubber block provided with a recess t formed to receive the head of the rod, and with a convex under surface fitting closely the bottom of the cavity in the socket or holderj'. It will be seen that the socket or holder, with the concave seat or surface to support the diaphragm, and the diaphragm formed with aconvex under surface to rest on said seat and with a convex upper surface to support the concave head h of the rod h, said diaphragm being secured by its margin to the socket or holder, constitute a simple and durable means for supporting the rod 71, and imparting to said rod the movements caused by variations of the steam-pressure.

It will be observed that the.

I prefer to extend the 4 IOC ing the diaphragm the necessary flexibility, and at the same time a suitable strength and firmness.

9' represents a cylindrical cap which is externally screw-threaded and formed to engage the internal screw-thread of the casing or holder j, said cap having a headj which supports the cross-bar m against the pressure of the spring 70. The headj has an orifice at its center, through which the rod 71 passes, said orifice being preferably formed to receive a boss or projection m" on the cross-bar m.

I claim 7 In a steam-pressure gage, the combination of the casing, the holderj, externally screwthreaded and engaged with an internallythreaded socket formed on the casing, the diaphragm secured at its margin in said casing MURDOCK MONEIL. Witnesses:

O. F. BROWN, A. D. HARRISON. 

